I'm not even sure that Mayo itself very clearly understands its own "hold" status.
From my personal experience:
2 people interview at Mayo on the same day, both are put on the "hold" status about a month and a half later. Both are told that they will remain there until April when the committee has finished all interviews.
Then, 1 month after being put on hold, one applicant is offered an acceptance with a full scholarship. The other still hasn't heard anything.
Just my 2cents, anecdotal as it may be.
Good luck everyone!